Electric lamp



Dec. 29,1925. I 1,567,852

S M. LUCAS,

ELECTRIC LAMP yo Filed August 24, 19 21 INVENTOR.

MM, 762; M

Patented Dec. 29, 1925.

s UNITED STATES PATENT OFFICE.

SAMUEL M. LUCAS, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

ELEornro LAMP.

Original application filed August 24, 1921, Serial No. 494,823. Patent No.'1',5 06,071, dated August '26, 1924. Divided and this application filed July 26, 1924. Serial No. 728,487.

To all whom it may concern:

Be it known that I, SAMUEL M. LUoAs, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Electrio Lamps, of which the following is a specification.

My invention relates to electric lamps and has for an object the provision of means for indicating at a distant point whether or not a lamp is lighted.

Apparatus embodying my invention is capable of general application, but is particularly well adapted for accomplishing the desired return indication when light signals are used in interlocking systems for railways.

The present application is a division ofmy copehding application, Serial No. 494; 823, filed on the 24th day of August,'1921', for electric lamps, now Patent No. 1,506,071, dated August 26, 1924.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof'in claims.

The accompanying drawing is a diagrammatic view showing one form of apparatus embodying my invention.

' Referring to the drawing, the. reference character S designatesa railway signal comprising two electric lamps G and R. Lamp G may be an incandescent filament lamp of the ordinary type, whereas lamp R is in the form of arectifier, comprising a filament 8 and two anodes 4 and 4", the filament and anodes all being enclosed in a bulb from which the air has been exhausted. The filament 3 constitutes the luminous or lighting element of the lamp R Located in front of the lamps G and'It are two lenses 2 and 2, respectively, which lenses may be colored green and red, respectively, and each of which serves to project a beam of light from the corresponding lamp when the lamp is lighted. In accordance with the usual practice the signal indicates proceed when lamp G is lighted, and stop when lamp R is lighted, the indication, of course, being determined by the color of the light beam projected by the signal.

The lamps in signal S are controlled by a lever L, which .is usually one of a plurality of similarlevers in an interlocking machine. As here shown, this lever is mounted to slide longitudinally, and is provided with a grip 5 to facilitate manipulation by hand. In accordance with usual interlocking practice, the lever L has three controlling positions, known as reverse, indicating, and normal positions, respectively. The control of the signal S is such that the proceed lamp G is lighted when the lever is in the reverse position, and that the stop lamp R is lighted when the lever is in the indicating and nor mal positions. As shown in the drawing, the lever is in the reverse position, the circuit for the proceed lamp G being from-the secondary of a transformer TF, through wire 15, contact 68 on lever L, wire 16, lamp Gr, wire 17 and common wire 0 to the secondary of transformer T. The primary of transformer T is supplied with alternating operating or lighting current from a source which is not shown in'the drawing.

\Vhen lever L is moved to the left from the position shown in the drawing, it is arrested in the indicating position-by the engagement of a latch 11 with a shoulder 21 on the lever. This movement of the lever opens contact 68, so that the proceed lamp G becomes extinguished, and this movement of the lever closes a contact 6-9, whereupon current flows from the secondary or transformer T through wire 15, contact 69, wire 18, the primary of transformer B, and wire 0 to the secondary of transformer T. The filament 3 of lamp R is connected with the secondary of transformer B, so that this filament then becomes lighted. While lever L is in the indicating position, a contact 710 is closed, the function of which contact is as follows:

The two anodes 4 and 4 are connected with the terminals of the primary of transformer B by wires 38 and 39, respectively, so that the potentials of these anodes alternate in accordance with the potentials of the terminals of the secondary of trans former T. A reactance 37. is connected across the secondary of transformer T When contact 7-1 0 is closed, the filament 3 is connected with the middle point of reactance 37 through a wire I, the primary of a transformer T wire 20, contact 107, and wire 40. If the filament 3 becomes hot enough to display the stop indication in response to the energization of transformer B, then during one-half of each cycle of the current supplied by transformer T the anode 45 will be positive with respect to the filament 3, whereupon current will flow from the left-hand terminal of the secondary of transformer T through common wire 0, Wire 38, anode 4 filament 3, wire I, primary of transformer T wire 20*, contact 10-7, wire 40', and the right-hand half of reactance 37 to the right-hand terminal of the secondary of transformer T During the other half of each cycle the anode 4' will be positive with respect to the filament, so that current will then flow from the right-hand terminal of the secondary of transformer T through wire 15, contact 69, wire 18, wire 39, anode 1 filament 3, wire I, primary of transformer T", wire 20*, contact 107, wire 40, and the lefthand half of reactance 37 to the secondary of transformer T During this latter half cycle anode 4 is negative with respect to filament 3, so that no current flows in the branch including this anode. Similarly, during the first half anode P is negative with respect to the filament, so that no current flows in the branch including this anode. The result of this alternate action of the two branches of the circuit for the primary of transformer T is to produce pulsating current in the primary of this transformer, which varies from minimum to maximum and back to minimum in the time required for the operating current to pass through one-half of the cycle. It follows that the frequency of the electro-motive force induced in the secondary of transformer T is twice the frequency of the operating or lighting current delivered by transformer T.

This double frequency current, which may be termed indication current, is delivered to a stator winding 14 of an induction motor M, the rotor 13 of which operates a centrifugal device C. This centrifugal device in turn actuates the latch 11 in such manner as to lift this latch out of the path of shoulder 21 on lever L when the centrifugal device operates at a predetermined speed. The centrifugal device G is so adjusted that when it is driven at a speed corresponding to current of twice the frequency of the current delivered by transformer T it will elevate the latch 11 to release the lever, but that if motor M should be operated by current of the frequency supplied by transformer T, the latch 11 will not be elevated, and so the lever will re main locked in the indicating position.

After the indication has been received, that is, after latch 11 is elevated, the lever L may be moved still further to the left to its normal position wherein contact 71O is opened, so that motor M is de-energized. Contact 69 remains closed, however, so that the stop lamp R continues to be lighted.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a railway signal comprising a rectifier having a filament and two anodes, a lever, means controlled by said lever for supplying operating current to said filament, an indication circuit including a source of alternating current and having two branches one of which includes said filament and one anode, and the other of which includes said filament and the other anode, and locking means for said lever controlled by the current flowing in said indication circuit.

2. In combination, a railway signal com prising a rectifier having a filament and two anodes, a lever, means controlled by said lever for supplying operating current to said filament, an indication circuit including a source of alternating current and having two branches, one of which includes said filament and one anode, and the other of which includes said filament and the other anode, and locking means for said lever controlled by the current in said in dication circuit and responsive to said current but not to current from said source for releasing said lever.

3. In combination, an electric lamp in the form of a rectifier having a filament and two anodes, means for supplying alternating lighting current to said filament, inclication means responsive to current of higher frequency than that of said lighting current but not to current ofthe frequency of said lighting current, and a circuit for controlling said indication means and including a source of alternating current, said circuit having two branches one of which includes said filament and one anode and the other of which includes said filament and the other anode.

4. In combination, an electric lamp in the form of a rectifier having a filament and two anodes, means for supplying alternating lighting current to said filament, an indication circuit supplied with currentfrom said lighting source and including the primary of a transformer, said circuit having two branches one of which includes said filament and one anode and the other of which in cludes said filament and the other anode, and indication means supplied with current from the secondary of said transformer and re sponsive to current of higher frequency than that of said lighting current but not to current of the frequency of said lighting current.

5. In combination, a railway signal comprising a lamp in the form of a rectifier having a filament and two anodes, a source of alternating current, a lever, means con trolled by said lever for supplying operating current to said filament from said source, an indication circuit supplied with current from said source and hav' i two branches one of which includes said filament and one anode and the other of which includes said filament and the other anode, means for locking said lever, and apparatus controlled by the current in said indication circuit and responsive to such current but not to the operating current supplied to said filament for releasing said locking means.

6. In combination, arailway signal comprising a lamp in the form of a rectifier hav ing a filament and two anodes, a source of alternating current, a lever havag proceed, indicating and stop positions, means controlled by said lever for supplying operating current to said filament from said source when the lever is in indicating and stop positions but not when it is in proceed position, an indication circuit supplied with current from said source and having two branches one of which includes said filament and one anode and the other of which includes said filament and the other anode, means for locking said lever in the indicating position while moving from the proceed towards the stop positions, and means controlled by the current in said indication circuit for releasing said locking means.

7. In combination, an electric lamp in the form of a rectifier having a filament and two anodes, means for supplying alternating lighting current to said filament, an indication circuit supplied with current from said lighting source and including the primary of a transformer, said circuit having two branches one of which includes said'filament and one anode and the other of which includes said filament and the other anode, and indication means supplied with current from the secondary of said transformer and responsive to current of twice the frequency of said lighting current but not to. current of the frequency of said lighting current.

8. In combination, a railway signal comprising a lamp in the form of a rectifier having a filament and two anodes, a source of alternating current, a lever, means controlled by said lever for supplying operating current to said filament from said source, an indication circuit supplied with current from said source and having two branches one of which includes said filament and one anode and the other of which includes said filament and the other anode, means for locking said lever, and apparatus controlled by the current in said indication circuit and responsive to current of twice the frequency of said operating current but not to current of the frequency of said operating current for releasing said locking means. a

9. In combination, a railway signal comprising a lamp in the form of a rectifier having a filament and two anodes, a source o alternating current, a lever, means controlled by said lever for supplying operating current to said filament from said source, an indication circuit supplied with current from said source and including the primary of a transformer, said circuit having two branches one of which includes the filament and one of said anodes and the other of which includes the filament and the other anode, a device for locking said lever, a motor receiving energy from the secondary of said transformer, and a centrifugal device operated by said motor for releasing said lever locking device when the motor receives alternating current of twice the frequency of said source but not when the motor receives current of the frequency of said source.

10. In combination, an electric lampin the form of a rectifier having a filament and two anodes, a transformer having a secondary connected with said filament, means for connecting the primary of said transformer with the two terminals of a source of alternating current, means for connecting one anode with one of said terminals and the other anode with the other of said terminals, means for connecting said filament with an intemediate point in said source, and indication means controlled by the current flowing in said last connecting means.

11. In combination, an incandescent electric lamp provided with two anodes, anode circuits for said lamps, a motor receiving energy from said anode circuits, a centrifugal device operated by said motor, and indication means for said lamp controlled by said centrifugal device.

In testimony whereof I aflix my signature.

SAMUEL M. LUCAS. 

